The Belarusian nobility refers to the social class of landowners and aristocrats in Belarus during the Grand Duchy of Lithuania and later the Polish-Lithuanian Commonwealth. This class played a significant role in the political, economic, and cultural life of the region, often holding significant power and influence. Many members of the Belarusian nobility were involved in military service and governance, contributing to the defense and administration of their territories. Over time, the decline of the nobility began with the partitions of Poland in the late 18th century, leading to changes in land ownership and social structure in Belarus.